Vm130 trubble

I use a vm130 in a car, Ford skyliner 1959, to operate the roof.
It has workd well for 3-4 years but suddenly I have a very bad reliability.
Allmost as the transmition was wery week.
Changing battery but don’t help. Check my conections don’t help.
Messuring battery that’s good.

Ok, something bad whit this so I bougt a new one, don’t help.

I did notice one thing: It’s mounted behind the dach in the car and there is a lot of cabels vith Dc 12V and some sheet metal.
If I put the reciver up behind the dach it don’t work even with the antenna hanging down under and the transmtter in the seat 1m away.
It dosen’t work there even if i put the transmitter up next to the reciver. If I let the reciver hanging down in the cables under the dach it
works up to 15-20 m avay.
It’s like it was an IR operated unit. No there isn’t any bad conections or broken cable. They are change several time.
Both the older and the new act’s the exact same way. I even tryed a third one with the same result
The car isn’t started so there is no current floing in the other cables that can create a magnetic feild there.
It’s as the fysikal location on the reciver is critical here. I did move the transmitter to the other side of the dach were there is les or no other cables that can disturbe but it’s no difference.
The green diod (power) is on all the time regardless of location.

Question: Wat can disturbe the Rf signal or the reciver? I did try this in my work shop and it is all shet metall in the walls and roof so I can’t listen to a normal FM radio inside.
Can this make a diferent with some kind of eco signal bounsing around in roof walls and dach?

Since it has worked for a couple or years and suddenly it does not work anymore, something must have changed.
Unfortunately, we are unable to determine what might have changed.
Maybe you performed a modification to the car, maybe you added something, maybe you removed something, etc…

I only added a cruise control but thats located in the engine bay.
what is this device sensitiv for? What can make it not resive a signal?

Or what I think: what can make it not understand it’s a signal it recive.
someting that can interfere whit the code in the signal?
Is it maybe sensitiv in the power supply. In that case maybe a condensator there will help?

You could add a cap close to the VM130, however, we doubt that the power supply is at the cause of troubles.